1 files changed, 61 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/profiles.hh b/third_party/nix/src/libstore/profiles.hh
new file mode 100644
index 000000000000..ab31cc993af5
--- /dev/null
+++ b/third_party/nix/src/libstore/profiles.hh
@@ -0,0 +1,61 @@
+#pragma once
+
+#include <time.h>
+
+#include "pathlocks.hh"
+#include "types.hh"
+
+namespace nix {
+
+struct Generation {
+  int number;
+  Path path;
+  time_t creationTime;
+  Generation() { number = -1; }
+  operator bool() const { return number != -1; }
+};
+
+typedef list<Generation> Generations;
+
+/* Returns the list of currently present generations for the specified
+   profile, sorted by generation number. */
+Generations findGenerations(const Path& profile, int& curGen);
+
+class LocalFSStore;
+
+Path createGeneration(const ref<LocalFSStore>& store, const Path& profile,
+                      const Path& outPath);
+
+void deleteGeneration(const Path& profile, unsigned int gen);
+
+void deleteGenerations(const Path& profile,
+                       const std::set<unsigned int>& gensToDelete, bool dryRun);
+
+void deleteGenerationsGreaterThan(const Path& profile, const int max,
+                                  bool dryRun);
+
+void deleteOldGenerations(const Path& profile, bool dryRun);
+
+void deleteGenerationsOlderThan(const Path& profile, time_t t, bool dryRun);
+
+void deleteGenerationsOlderThan(const Path& profile, const string& timeSpec,
+                                bool dryRun);
+
+void switchLink(const Path& link, Path target);
+
+/* Ensure exclusive access to a profile.  Any command that modifies
+   the profile first acquires this lock. */
+void lockProfile(PathLocks& lock, const Path& profile);
+
+/* Optimistic locking is used by long-running operations like `nix-env
+   -i'.  Instead of acquiring the exclusive lock for the entire
+   duration of the operation, we just perform the operation
+   optimistically (without an exclusive lock), and check at the end
+   whether the profile changed while we were busy (i.e., the symlink
+   target changed).  If so, the operation is restarted.  Restarting is
+   generally cheap, since the build results are still in the Nix
+   store.  Most of the time, only the user environment has to be
+   rebuilt. */
+string optimisticLockProfile(const Path& profile);
+
+}  // namespace nix